I recently upgraded a 2 nodes cluster (cascading) from HACMP/ES 4.4.0
to HACMP/ES 4.4.1, and the cluster behaves weirdly! After upgrading
the primary node, and after a reboot (as per documentation), I restart
cluster manager. The node is joigning the cluster, then the resource
group travel gently from the backup node to the fresh upgraded primary
node. Everything is fine, filesystems are mounted, application server
is started, then when you think you are done, a swap adapter event
occurred on the node, and the standby adapter becomes the service
adapter. After all the software and hardware checking, I couldn't find
any trouble on the adapter...
Did you notice such behaviour?